Pub Date : 2025-12-17DOI: 10.1016/j.optcom.2025.132787
A.K. Sharma
A broadband interferometer using either metallic mirrors or air-glass/glass-air interface as partial mirrors is presented to obtain cross-field correlation signals for dispersion measurement of interfaces and optical materials. Correlation signals are analyzed for quantitative estimation of group delay dispersion using direct time domain fringe demodulation, temporal phase and spectral phase of cross-field correlations using Fourier and Hilbert transformation. Simpler approaches of electronic demodulation of cross-field correlation and color camera acting as spectral filter cum detector are presented to avoid use of optical spectral filters or spectrometer to obtain spectrally dependent group delays through electronic phase, spectral and frequency filters for the first time. Effects of spectral response of detector and temporal chirp on estimated spectral frequencies are also discussed. Experimental results are compared with theory.
{"title":"Broadband cross-field white light correlations for study of dispersive characteristic of optical interfaces and materials","authors":"A.K. Sharma","doi":"10.1016/j.optcom.2025.132787","DOIUrl":"10.1016/j.optcom.2025.132787","url":null,"abstract":"<div><div>A broadband interferometer using either metallic mirrors or air-glass/glass-air interface as partial mirrors is presented to obtain cross-field correlation signals for dispersion measurement of interfaces and optical materials. Correlation signals are analyzed for quantitative estimation of group delay dispersion using direct time domain fringe demodulation, temporal phase and spectral phase of cross-field correlations using Fourier and Hilbert transformation. Simpler approaches of electronic demodulation of cross-field correlation and color camera acting as spectral filter cum detector are presented to avoid use of optical spectral filters or spectrometer to obtain spectrally dependent group delays through electronic phase, spectral and frequency filters for the first time. Effects of spectral response of detector and temporal chirp on estimated spectral frequencies are also discussed. Experimental results are compared with theory.</div></div><div><h3>Pacs codes</h3><div>42.65 Re (ultrafast phenomenon).</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"603 ","pages":"Article 132787"},"PeriodicalIF":2.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.optcom.2025.132788
Dancui Li , Yanni Zhang , Yangyang Li
Polarization imaging is crucial for target detection and identification and has broad applications in numerous technical fields. However, traditional polarization detection systems often suffer from bulky and complexity, creating a pressing need for compact, real-time polarization imaging lenses. Metasurfaces can perform high-performance multi-functional integration by precisely manipulating optical wavefronts. Here, we demonstrate a broadband achromatic polarized metalens composed of anisotropic nanofins. These nanofins provide additional control over the dispersion and phase of the output light via a polarization-dependent phase optimization method. As a result, the designed achromatic polarized metalens achieves broadband focusing for incident light with different polarization states and exhibits negligible crosstalk, effectively improving the device's practicality. This work demonstrates the potential of the proposed metalens for applications in color imaging, machine vision, vectorial optical field manipulation, anti-counterfeiting, and atmospheric detection.
{"title":"A broadband achromatic multi-polarization channels metasurface with negligible-crosstalk focusing in the visible","authors":"Dancui Li , Yanni Zhang , Yangyang Li","doi":"10.1016/j.optcom.2025.132788","DOIUrl":"10.1016/j.optcom.2025.132788","url":null,"abstract":"<div><div>Polarization imaging is crucial for target detection and identification and has broad applications in numerous technical fields. However, traditional polarization detection systems often suffer from bulky and complexity, creating a pressing need for compact, real-time polarization imaging lenses. Metasurfaces can perform high-performance multi-functional integration by precisely manipulating optical wavefronts. Here, we demonstrate a broadband achromatic polarized metalens composed of anisotropic nanofins. These nanofins provide additional control over the dispersion and phase of the output light via a polarization-dependent phase optimization method. As a result, the designed achromatic polarized metalens achieves broadband focusing for incident light with different polarization states and exhibits negligible crosstalk, effectively improving the device's practicality. This work demonstrates the potential of the proposed metalens for applications in color imaging, machine vision, vectorial optical field manipulation, anti-counterfeiting, and atmospheric detection.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132788"},"PeriodicalIF":2.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.optcom.2025.132777
Zhongyuan Wu, Yanchen Fang, Sicheng Jiang, Fengchun Qiu, Zeren Zhao, Ming Chen, Yiqi Li, Yuanbo Du, Hsien-chi Yeh
A weak-light digital optical phase-locked loop has been developed for space-based gravitational wave detection, where a frequently occurring phenomenon of false locking can severely degrade the phase noise floor. Based on a phase modulation model, false locking is identified as being primarily induced by additional phase shifts within the digital loop. Through loop calibration and modulation experiments, the quantitative relationships between false-locking characteristics (modulation frequency and depth) and loop parameters (delay and bandwidth) are systematically investigated. Several effective strategies are further proposed to eliminate false locking. Benefiting from active frequency feedback, the loop bandwidth has been extended to 130 kHz with the phase noise suppressed to while the optical power of the received weak laser is as low as 0.2 nW. This work offers a valuable guidance for optimizing the design of the digital phase-locked loop in the space-based gravitational wave detection mission.
{"title":"False locking in a digital optical phase-locked system for space-based gravitational wave detection","authors":"Zhongyuan Wu, Yanchen Fang, Sicheng Jiang, Fengchun Qiu, Zeren Zhao, Ming Chen, Yiqi Li, Yuanbo Du, Hsien-chi Yeh","doi":"10.1016/j.optcom.2025.132777","DOIUrl":"10.1016/j.optcom.2025.132777","url":null,"abstract":"<div><div>A weak-light digital optical phase-locked loop has been developed for space-based gravitational wave detection, where a frequently occurring phenomenon of false locking can severely degrade the phase noise floor. Based on a phase modulation model, false locking is identified as being primarily induced by additional phase shifts within the digital loop. Through loop calibration and modulation experiments, the quantitative relationships between false-locking characteristics (modulation frequency and depth) and loop parameters (delay and bandwidth) are systematically investigated. Several effective strategies are further proposed to eliminate false locking. Benefiting from active frequency feedback, the loop bandwidth has been extended to <span><math><mo>∼</mo></math></span> 130 kHz with the phase noise suppressed to <span><math><mrow><mo>∼</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup><mspace></mspace><mi>rad</mi><mo>/</mo><msqrt><mrow><mi>Hz</mi></mrow></msqrt></mrow></math></span> while the optical power of the received weak laser is as low as 0.2 nW. This work offers a valuable guidance for optimizing the design of the digital phase-locked loop in the space-based gravitational wave detection mission.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132777"},"PeriodicalIF":2.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-17DOI: 10.1016/j.optcom.2025.132782
Hao Luo , Ning Xu , Shengyi Wang , Hanzhuo Kuang , Hua Ge , Xiang Li , Bowen Jia
Mid-infrared (MIR) silicon photonics exhibits significant potential for integrated sensing and communication (ISAC) applications. In this work, an InAs detection system on silicon-on-insulator (SOI) via heteroepitaxial integration is proposed. The detection system employs a grating coupler for the input of the MIR light, achieving a maximum coupling efficiency of 35.3 %. The light evanescently couples from the waveguide to the active layer of the InAs photodetector (PD) through precisely engineered GaAs/Ge buffer structures that accommodate lattice mismatches between InAs and silicon. Optical simulations systematically evaluate buffer thicknesses and compare alternative epitaxial architectures. The optimized 20 μm-long integrated waveguide PD demonstrates absorption efficiency exceeding 95 % with a 3 dB bandwidth of 21.51 GHz. Electrical simulations analyse dark current mechanisms, revealing a responsivity of 0.81 A/W at 3 μm and a detectivity of 2.34 × 109 cm Hz1/2 W−1 at −1 V bias and 300 K. The introduction of a pBn architecture reduces the dark current density by 58.5 %, thereby further increasing the detectivity to 2.65 × 109 cm Hz1/2 W−1. The influence of integration and fabrication processes on the overall device performance is also discussed. This study demonstrates a promising integrated optics approach for highly efficient MIR detection, paving the way for advanced on-chip photonic applications.
中红外（MIR）硅光子学显示出集成传感和通信（ISAC）应用的巨大潜力。本文提出了一种基于异质外延集成的绝缘体上硅（SOI） InAs检测系统。该检测系统采用光栅耦合器作为MIR光的输入，最大耦合效率为35.3%。光通过精确设计的砷化镓/锗缓冲结构从波导瞬变耦合到InAs光电探测器（PD）的有源层，以适应InAs和硅之间的晶格不匹配。光学模拟系统地评估缓冲厚度和比较不同的外延架构。优化后的20 μm长集成波导PD的吸收效率超过95%，3db带宽为21.51 GHz。电学模拟分析了暗电流机制，发现在3 μm下的响应率为0.81 a /W，在−1 V偏置和300 K下的探测率为2.34 × 109 cm Hz1/2 W−1。pBn结构的引入使暗电流密度降低了58.5%，从而进一步将探测率提高到2.65 × 109 cm Hz1/2 W−1。还讨论了集成和制造工艺对器件整体性能的影响。这项研究展示了一种有前途的集成光学方法，用于高效的MIR检测，为先进的片上光子应用铺平了道路。
{"title":"Design and modelling of InAs detection system on SOI via monolithic integration for mid-infrared integrated sensing and communication","authors":"Hao Luo , Ning Xu , Shengyi Wang , Hanzhuo Kuang , Hua Ge , Xiang Li , Bowen Jia","doi":"10.1016/j.optcom.2025.132782","DOIUrl":"10.1016/j.optcom.2025.132782","url":null,"abstract":"<div><div>Mid-infrared (MIR) silicon photonics exhibits significant potential for integrated sensing and communication (ISAC) applications. In this work, an InAs detection system on silicon-on-insulator (SOI) via heteroepitaxial integration is proposed. The detection system employs a grating coupler for the input of the MIR light, achieving a maximum coupling efficiency of 35.3 %. The light evanescently couples from the waveguide to the active layer of the InAs photodetector (PD) through precisely engineered GaAs/Ge buffer structures that accommodate lattice mismatches between InAs and silicon. Optical simulations systematically evaluate buffer thicknesses and compare alternative epitaxial architectures. The optimized 20 μm-long integrated waveguide PD demonstrates absorption efficiency exceeding 95 % with a 3 dB bandwidth of 21.51 GHz. Electrical simulations analyse dark current mechanisms, revealing a responsivity of 0.81 A/W at 3 μm and a detectivity of 2.34 × 10<sup>9</sup> cm Hz<sup>1/2</sup> W<sup>−1</sup> at −1 V bias and 300 K. The introduction of a pBn architecture reduces the dark current density by 58.5 %, thereby further increasing the detectivity to 2.65 × 10<sup>9</sup> cm Hz<sup>1/2</sup> W<sup>−1</sup>. The influence of integration and fabrication processes on the overall device performance is also discussed. This study demonstrates a promising integrated optics approach for highly efficient MIR detection, paving the way for advanced on-chip photonic applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132782"},"PeriodicalIF":2.5,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.optcom.2025.132778
Xiangwei Liu, Mohan Ding, Yonghong Wang, Peizheng Yan
Speckle noise is a critical factor limiting the application of speckle pattern interferometry. To address this issue, this study proposes a speckle noise suppression method based on polarization diversity. With a polarization camera, multiple polarization state channels are constructed within a single speckle interferogram, and channel information is fused through a complex amplitude averaging algorithm. The theoretical principles and specific extent of noise reduction achieved by this method are derived. Comprehensive and objective comparison experiments are conducted, and the experimental results align well with the theoretical derivations, demonstrating that this method can effectively suppress speckle noise in phase fringe patterns.
{"title":"Polarization diversity-based speckle noise suppression method in speckle pattern interferometry","authors":"Xiangwei Liu, Mohan Ding, Yonghong Wang, Peizheng Yan","doi":"10.1016/j.optcom.2025.132778","DOIUrl":"10.1016/j.optcom.2025.132778","url":null,"abstract":"<div><div>Speckle noise is a critical factor limiting the application of speckle pattern interferometry. To address this issue, this study proposes a speckle noise suppression method based on polarization diversity. With a polarization camera, multiple polarization state channels are constructed within a single speckle interferogram, and channel information is fused through a complex amplitude averaging algorithm. The theoretical principles and specific extent of noise reduction achieved by this method are derived. Comprehensive and objective comparison experiments are conducted, and the experimental results align well with the theoretical derivations, demonstrating that this method can effectively suppress speckle noise in phase fringe patterns.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132778"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents an edge filtering-based interrogation method for multiple Fiber Bragg grating (FBG) sensors by enabling effective quasi-distributed sensing using a commercial optical time-domain reflectometer (OTDR). The proposed edge filter is designed and optimized by a 4.5 cm multimode fiber (MMF) spliced between two single-mode fibers (SMFs) to form a single-multi-single mode (SMS) cascaded structure. This edge filter design is adaptable to various FBG centre wavelengths by optimizing MMF length, allowing a broad interrogation range. In the experimental setup, we implemented three FBG sensors along with SMS edge filter and OTDR, where FBG wavelength shifts caused by temperature and strain changes are converted to power variations through the edge filter, enabling accurate measurements. This configuration allows simultaneous monitoring of temperature and strain. The experimental results show the temperature sensitivity of in the range of , and the strain sensitivity of across . Although the system's stability, repeatability, and hysteresis were evaluated for both measurements, OTDR-based sensing systems with multiple sensing probes are still susceptible to optical power fluctuations arising from system instabilities and experimental uncertainties, which can lead to significant measurement inaccuracies. To ensure precise and reliable sensing performance, a machine learning (ML)-based approach was implemented to access measurement accuracy. The proposed edge filter offers high accuracy with high sensitivity and resolution, low cost, and the ability for independent multipoint and multiparameter measurements, enhancing its FBG selectivity for quasi-distributed sensing.
{"title":"Machine learning-assisted quasi-distributed FBG sensing using SMS edge filtering and OTDR","authors":"Anirban Majee , Kerry Thubru , Nikhil Vangety , Koustav Dey , Sourabh Roy","doi":"10.1016/j.optcom.2025.132784","DOIUrl":"10.1016/j.optcom.2025.132784","url":null,"abstract":"<div><div>This study presents an edge filtering-based interrogation method for multiple Fiber Bragg grating (FBG) sensors by enabling effective quasi-distributed sensing using a commercial optical time-domain reflectometer (OTDR). The proposed edge filter is designed and optimized by a 4.5 cm multimode fiber (MMF) spliced between two single-mode fibers (SMFs) to form a single-multi-single mode (SMS) cascaded structure. This edge filter design is adaptable to various FBG centre wavelengths by optimizing MMF length, allowing a broad interrogation range. In the experimental setup, we implemented three FBG sensors along with SMS edge filter and OTDR, where FBG wavelength shifts caused by temperature and strain changes are converted to power variations through the edge filter, enabling accurate measurements. This configuration allows simultaneous monitoring of temperature and strain. The experimental results show the temperature sensitivity of <span><math><mrow><mn>3.63</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>2</mn></mrow></msup><mspace></mspace><mi>d</mi><mi>B</mi><mo>/</mo><mo>°C</mo></mrow></math></span> in the range of <span><math><mrow><mn>30</mn><mo>−</mo><mn>200</mn><mspace></mspace><mo>°C</mo></mrow></math></span>, and the strain sensitivity of <span><math><mrow><mn>3.34</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup><mspace></mspace><mi>d</mi><mi>B</mi><mo>/</mo><mi>μ</mi><mi>ε</mi></mrow></math></span> across <span><math><mrow><mn>0</mn><mo>−</mo><mn>2000</mn><mspace></mspace><mi>μ</mi><mi>ε</mi></mrow></math></span>. Although the system's stability, repeatability, and hysteresis were evaluated for both measurements, OTDR-based sensing systems with multiple sensing probes are still susceptible to optical power fluctuations arising from system instabilities and experimental uncertainties, which can lead to significant measurement inaccuracies. To ensure precise and reliable sensing performance, a machine learning (ML)-based approach was implemented to access measurement accuracy. The proposed edge filter offers high accuracy with high sensitivity and resolution, low cost, and the ability for independent multipoint and multiparameter measurements, enhancing its FBG selectivity for quasi-distributed sensing.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132784"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.optcom.2025.132780
Naihan Zhang , Mengyao Han , Muguang Wang , Ran Pang , Chang Cao , Xiongyan Tang
In this paper, we propose and experimentally demonstrate a high-resolution sensing demodulation technique using optical vector analysis based on microwave photonics (MWP). By employing optical single-sideband modulation and high-precision microwave frequency sweeping, the full complex response of the fiber-optic sensing probe, including both amplitude and phase information, is accurately reconstructed. This approach enables direct mapping of small optical spectral shifts into great microwave frequency deviations, achieving ultra-high sensing resolution. The resolution of the proposed system is only determined by the frequency resolution of the measurement instrument, and is not limited by factors such as the free spectral range. To evaluate the system performance, the temperature response of a fiber Bragg grating Fabry-Perot sensor is experimentally characterized. A high sensitivity of 1.21 GHz/°C is achieved, with a measurement resolution as high as 8.26 × 10−6 °C. Furthermore, the method is successfully applied to a Mach-Zehnder interferometer, demonstrating its universality across different types of fiber structures. Compared to existing MWP-based sensing techniques, the proposed method offers superior resolution and demodulation flexibility.
{"title":"Fiber optic sensing demodulation utilizing optical vector analysis based on microwave photonics","authors":"Naihan Zhang , Mengyao Han , Muguang Wang , Ran Pang , Chang Cao , Xiongyan Tang","doi":"10.1016/j.optcom.2025.132780","DOIUrl":"10.1016/j.optcom.2025.132780","url":null,"abstract":"<div><div>In this paper, we propose and experimentally demonstrate a high-resolution sensing demodulation technique using optical vector analysis based on microwave photonics (MWP). By employing optical single-sideband modulation and high-precision microwave frequency sweeping, the full complex response of the fiber-optic sensing probe, including both amplitude and phase information, is accurately reconstructed. This approach enables direct mapping of small optical spectral shifts into great microwave frequency deviations, achieving ultra-high sensing resolution. The resolution of the proposed system is only determined by the frequency resolution of the measurement instrument, and is not limited by factors such as the free spectral range. To evaluate the system performance, the temperature response of a fiber Bragg grating Fabry-Perot sensor is experimentally characterized. A high sensitivity of 1.21 GHz/°C is achieved, with a measurement resolution as high as 8.26 × 10<sup>−6</sup> °C. Furthermore, the method is successfully applied to a Mach-Zehnder interferometer, demonstrating its universality across different types of fiber structures. Compared to existing MWP-based sensing techniques, the proposed method offers superior resolution and demodulation flexibility.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132780"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.optcom.2025.132786
Kangni Wang, Yuqing Gu, Yun Qiu, Linyong Qian
A guided-mode resonance (GMR) grating-based dual-band graphene absorber is theoretically proposed for the shortwave infrared range. The absorber comprises two pairs of electrodes: the bottom electrode consists of a graphene layer and an intermediate metal layer that controls the electro-optic (EO) waveguide layer, while the top electrode includes an intermediate metal layer and a top indium tin oxide layer that controls the EO grating. This configuration enables two independently tunable absorption bands, corresponding to the metal-assisted GMR and surface plasmon resonance modes. The enhanced absorption results from the combined effects of both the graphene and the metal layers. Numerical simulations indicate that the two absorption bands exhibit distinct and separate electric field distributions while achieving high absorption rates above 90 % during EO tuning. A linearly negative spectral shift of −1.8036 nm/V and −3.1146 nm/V is observed for the bands at shorter and longer wavelengths, respectively. By adjusting the geometric parameters of the structure, a broader spectral range encompassing two absorption bands can be realized. Due to its independent tunability and high absorption, the proposed device holds great potential for applications in detectors, sensors, and modulators.
{"title":"Dual-band independently tunable graphene absorber based on guided-mode resonance gratings","authors":"Kangni Wang, Yuqing Gu, Yun Qiu, Linyong Qian","doi":"10.1016/j.optcom.2025.132786","DOIUrl":"10.1016/j.optcom.2025.132786","url":null,"abstract":"<div><div>A guided-mode resonance (GMR) grating-based dual-band graphene absorber is theoretically proposed for the shortwave infrared range. The absorber comprises two pairs of electrodes: the bottom electrode consists of a graphene layer and an intermediate metal layer that controls the electro-optic (EO) waveguide layer, while the top electrode includes an intermediate metal layer and a top indium tin oxide layer that controls the EO grating. This configuration enables two independently tunable absorption bands, corresponding to the metal-assisted GMR and surface plasmon resonance modes. The enhanced absorption results from the combined effects of both the graphene and the metal layers. Numerical simulations indicate that the two absorption bands exhibit distinct and separate electric field distributions while achieving high absorption rates above 90 % during EO tuning. A linearly negative spectral shift of −1.8036 nm/V and −3.1146 nm/V is observed for the bands at shorter and longer wavelengths, respectively. By adjusting the geometric parameters of the structure, a broader spectral range encompassing two absorption bands can be realized. Due to its independent tunability and high absorption, the proposed device holds great potential for applications in detectors, sensors, and modulators.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132786"},"PeriodicalIF":2.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.optcom.2025.132771
Chirang R. Patel, Bhargav Cheekati, Ashok Kumar
We investigate the effects of atmospheric turbulence on a deterministic secure quantum communication protocol that utilizes the squeezing phase of a two-mode squeezed state. The protocol enables direct communication by encoding information in the squeezing phase, which is accessible only through joint measurements on both modes. Since individual modes do not reveal any squeezing phase information, the protocol possesses inherent security. To evaluate its practical feasibility, we analyze its performance over a free-space optical channel under realistic conditions, accounting for loss and excess noise. Our results show that the protocol operates effectively for distances exceeding 60 km under a refractive index structure constant of , over 30 km for , and above 15 km for in a ground-based horizontal free-space optical channel. Moreover, optimizing the beam waist and detector size can further enhance the protocol’s robustness against varying turbulence conditions. This work demonstrates the potential for implementing squeezing-phase-based deterministic secure quantum communication for ground-based free-space optical channels, thereby advancing the prospects of practical quantum secure communication in challenging environments.
{"title":"Impact of atmospheric turbulence on free-space deterministic secure quantum communication with squeezed light","authors":"Chirang R. Patel, Bhargav Cheekati, Ashok Kumar","doi":"10.1016/j.optcom.2025.132771","DOIUrl":"10.1016/j.optcom.2025.132771","url":null,"abstract":"<div><div>We investigate the effects of atmospheric turbulence on a deterministic secure quantum communication protocol that utilizes the squeezing phase of a two-mode squeezed state. The protocol enables direct communication by encoding information in the squeezing phase, which is accessible only through joint measurements on both modes. Since individual modes do not reveal any squeezing phase information, the protocol possesses inherent security. To evaluate its practical feasibility, we analyze its performance over a free-space optical channel under realistic conditions, accounting for loss and excess noise. Our results show that the protocol operates effectively for distances exceeding 60 km under a refractive index structure constant of <span><math><mrow><msubsup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>15</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>m</mtext></mrow><mrow><mo>−</mo><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span>, over 30 km for <span><math><mrow><msubsup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>14</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>m</mtext></mrow><mrow><mo>−</mo><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span>, and above 15 km for <span><math><mrow><msubsup><mrow><mi>C</mi></mrow><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></msubsup><mo>=</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>13</mn></mrow></msup><mspace></mspace><msup><mrow><mtext>m</mtext></mrow><mrow><mo>−</mo><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span> in a ground-based horizontal free-space optical channel. Moreover, optimizing the beam waist and detector size can further enhance the protocol’s robustness against varying turbulence conditions. This work demonstrates the potential for implementing squeezing-phase-based deterministic secure quantum communication for ground-based free-space optical channels, thereby advancing the prospects of practical quantum secure communication in challenging environments.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132771"},"PeriodicalIF":2.5,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-15DOI: 10.1016/j.optcom.2025.132756
Xin Tong , Junyong Zhang , Xingqiang Lu
Fermat spiral is introduced into reflection photon sieves (PS) to achieve the generation of femtosecond optical vortex (OV) pulses, and the cyclic radial-shearing interferometer is used for lateral-shearing interferometry to measure the chirality and topological charge (TC). The loop interferometry meets the requirement of zero optical path difference (OPD), effectively solving the challenge caused by the short coherence length of ultrashort pulse lasers or broadband light sources. The above interference experiments are carried out and prove the effectiveness of our proposed method that provides a novel solution for the generation and efficient measurement of ultrashort OV pulses with simple operation and high adaptability.
{"title":"Lateral-shearing interferometry for femtosecond optical vortex focusing of reflection Fermat-spiral photon sieves using cyclic radial-shearing interferometer","authors":"Xin Tong , Junyong Zhang , Xingqiang Lu","doi":"10.1016/j.optcom.2025.132756","DOIUrl":"10.1016/j.optcom.2025.132756","url":null,"abstract":"<div><div>Fermat spiral is introduced into reflection photon sieves (PS) to achieve the generation of femtosecond optical vortex (OV) pulses, and the cyclic radial-shearing interferometer is used for lateral-shearing interferometry to measure the chirality and topological charge (TC). The loop interferometry meets the requirement of zero optical path difference (OPD), effectively solving the challenge caused by the short coherence length of ultrashort pulse lasers or broadband light sources. The above interference experiments are carried out and prove the effectiveness of our proposed method that provides a novel solution for the generation and efficient measurement of ultrashort OV pulses with simple operation and high adaptability.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"602 ","pages":"Article 132756"},"PeriodicalIF":2.5,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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